[Bug c++/31502] New: gcc/g++ randomly seg faults, sometimes freezes the entire machine

["ye dot patrick at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

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Machine info:
  CPU: AMD 4200+ (64 bit)
  RAM: 3G DDR

OS info:
  Type: Linux
  Distro: Ubuntu Edgy 6.10
  Kernel: 2.6.17-10-generic #2 SMP Tue Dec 5 22:28:26 UTC 2006 i686 GNU/Linu
  Bit: 32 bit OS

Overview of the problem: gcc and g++ would frequently and randomly seg faults,
and this would sometimes freeze the machine and force the "reset" button to be
pressed.

Code on which these errors have occurred: mplayer 1.0pre8, Blender.

Example of compilation command that produces the error:

gcc -c -O3 -g  -Wdeclaration-after-statement -Wall -Wno-switch
-DHAVE_AV_CONFIG_H -I..
-I/home/jingy/install/blender/cvs_new/blender/extern/ffmpeg/libavutil
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE  -DHAVE_AV_CONFIG_H
-DMOZ_NOT_NET snow.c -o
/home/jingy/install/blender/cvs_new/blender/obj/linux-glibc2.4-i386/extern/ffmpeg/libavcodec/snow.o


Output of the compiler:

---

snow.c: In function ‘pred_mv’:
snow.c:1961: warning: suggest parentheses around + or - inside shift
snow.c:1962: warning: suggest parentheses around + or - inside shift
snow.c:1963: warning: suggest parentheses around + or - inside shift
snow.c:1964: warning: suggest parentheses around + or - inside shift
snow.c:1965: warning: suggest parentheses around + or - inside shift
snow.c:1966: warning: suggest parentheses around + or - inside shift
snow.c: In function ‘encode_q_branch’:
snow.c:1994: warning: initialization discards qualifiers from pointer target
type
snow.c:1995: warning: initialization discards qualifiers from pointer target
type
snow.c:1996: warning: initialization discards qualifiers from pointer target
type
snow.c:1997: warning: initialization discards qualifiers from pointer target
type
snow.c: In function ‘encode_q_branch2’:
snow.c:2221: warning: initialization discards qualifiers from pointer target
type
snow.c:2222: warning: initialization discards qualifiers from pointer target
type
snow.c: In function ‘decode_q_branch’:
snow.c:2274: warning: initialization discards qualifiers from pointer target
type
snow.c:2275: warning: initialization discards qualifiers from pointer target
type
snow.c: In function ‘pred_block’:
snow.c:2497: warning: suggest parentheses around && within ||
snow.c: In function ‘ff_snow_inner_add_yblock’:
snow.c:2538: warning: left shift count is negative
snow.c: In function ‘add_yblock_buffered’:
snow.c:2567: warning: unused variable ‘y’
snow.c:2567: warning: unused variable ‘x’
snow.c:2555: warning: unused variable ‘dst’
snow.c: In function ‘add_yblock’:
snow.c:2809: warning: initialization discards qualifiers from pointer target
type
snow.c:2821: warning: left shift count is negative
snow.c: In function ‘predict_slice_buffered’:
snow.c:2896: warning: passing argument 5 of ‘add_yblock_buffered’ discards
qualifiers from pointer target type
snow.c: In function ‘get_block_bits’:
snow.c:3028: warning: initialization discards qualifiers from pointer target
type
snow.c:3029: warning: initialization discards qualifiers from pointer target
type
snow.c: In function ‘get_block_rd’:
snow.c:3065: warning: unused variable ‘obmc’
snow.c: In function ‘get_4block_rd’:
snow.c:3182: warning: passing argument 2 of ‘add_yblock’ discards qualifiers
from pointer target type
snow.c:3168: warning: unused variable ‘b_height’
snow.c: In function ‘common_init’:
snow.c:3872: warning: assignment from incompatible pointer type
snow.c:3872: warning: assignment from incompatible pointer type
snow.c:3873: warning: assignment from incompatible pointer type
snow.c:3873: warning: assignment from incompatible pointer type
snow.c:3874: warning: assignment from incompatible pointer type
snow.c:3874: warning: assignment from incompatible pointer type
snow.c:3875: warning: assignment from incompatible pointer type
snow.c:3875: warning: assignment from incompatible pointer type
snow.c: At top level:
snow.c:1327: warning: ‘spatial_compose53i’ defined but not used
snow.c:1494: warning: ‘spatial_compose97i’ defined but not used
snow.c: In function ‘get_dc’:
snow.c:3021: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
For Debian GNU/Linux specific bug reporting instructions,
see <URL:file:///usr/share/doc/gcc-4.1/README.Bugs>.
The bug is not reproducible, so it is likely a hardware or OS problem.
make[3]: ***
[/home/jingy/install/blender/cvs_new/blender/obj/linux-glibc2.4-i386/extern/ffmpeg/libavcodec/snow.o]
Error 1
make[2]: *** [all] Error 1
make[1]: *** [all] Error 1
make: *** [all] Error 1

---

The output of the preprocessor (snow.i) can be downloaded from:

http://www.csse.unimelb.edu.au/~jingy/download/snow.i


Sometimes these errors would be immediately followed by a kernel warning
stating  some memory protection has failed. Sometimes these errors would be so
severe that no other processes can be run.

Please feel free to contact me for further information.

Thanks a lot.

Patrick


-- 
           Summary: gcc/g++ randomly seg faults, sometimes freezes the
                    entire machine
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ye dot patrick at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31502